This invention relates to a sharpener for self-sharpening feed chopping knives and the like, and more particularly, but not by way of limitation, to a sharpener having means for pivoting upwardly a sharpening stone and a stone holder housing away from the cutting edge of the chopping knives to prevent potential breakage of the sharpening stone.
This invention relates to an improved structure of an adjustable sharpener for self-sharpening feed chopping knives disclosed in U.S. Pat. No. 4,031,670. The invention described in this patent, while greatly improving the operation of self-sharpening feed chopping knives continuously during the cutting of crops, forage, ensilage and the like, did not include structure to allow the pivoting of the stone holder housing and stone out of the chopper box when the knives had been sharpened. Heretofore the sharpening stone was exposed to potential breakage from foreign material being trapped between the cutting edge of the knives and the sharpening stone as the knives are continuously sharpened during the cutting operation and causing breakage of expensive sharpening stones.
The subject invention eliminates having to expose the sharpening stone mounted in the stone holder housing continuously to the rotating cutter head and chopping knives inside the chopper box.